Selective Decomposition of Alkyl Hydroperoxides on H-Type Zeolite via a Concerted Approach

Abstract

Catalyzed by H-type zeolite, the selective decomposition of alkyl hydroperoxides (HP), including 1-phenylethyl hydroperoxide (PEHP), phenylmethyl hydroperoxide (PMHP), and methyl hydroperoxide (MHP), to their corresponding carbonyl compounds and H2O have been investigated by DFT calculations. In this calculation, a 19-atom cluster containing four tetrahedral atoms (denoted as 4T) was used to model the H-type zeolite catalyst, and two competitive reaction channels were evaluated. Calculations predict that the concerted reaction channel is favorable for selective decomposition of alkyl hydroperoxides on the H-type zeolite from both kinetics and thermodynamics points of view. We found that the rate-determining step of the stepwise reaction channel proceeds via a one-hydrogen-bond transition state followed by dehydration. In the concerted reaction channel, whose transition state is an eight-membered ring with two hydrogen bonds, the decomposition of hydroperoxides occurs synchronously to form carbonyl compounds and H2O, involving the proton exchange between hydroperoxides and the zeolite.